Pyrolysis Of Pine Wood Sawdust Research Articles

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics.

Pyrolysis of lignocellulosic biomass and waste plastics has been intensely studied in the last few decades to obtain renewable fuels and chemicals. Various pyrolysis devices have been developed for use in a laboratory setting, operated either in batch or continuously at scales ranging from milligrams per hour to tenths of g per hour. We report here the design and operation of a novel staged free-fall (catalytic) pyrolysis unit and demonstrate that the concept works very well for the (catalytic) pyrolysis of pinewood sawdust, paper sludge, and polypropylene as representative feeds. The unit consists of a vertical tube with a pretreatment section, a pyrolysis section, a solid residue collection section, a gas-liquid separation/collection section, and a catalytic reaction section to optionally perform ex situ catalytic upgrading of the pyrolysis vapor. The sample is placed in a tube, which is transported by gravity through various sections of the unit. It allows for rapid testing with semicontinuous feeding (e.g., 50 g h-1) and the opportunity to perform reactions under an (inert) gas (e.g., N2) at atmospheric as well as elevated pressure (e.g., 50 bar). Liquid yields for noncatalytic sawdust pyrolysis at optimized conditions (475 °C and atmospheric pressure) were 63 wt % on biomass intake. A lower yield of 51 wt % (on a biomass basis) was obtained for the noncatalytic pyrolysis of paper sludge, likely due to the presence of minerals (e.g., CaCO3) in the feed. The possibility of using the unit for ex situ catalytic pyrolysis (pyrolysis at 475 °C and catalytic upgrading at 550 °C) was also successfully demonstrated using paper sludge as the feed and H-ZSM-5 as the catalyst (21 wt % catalyst on biomass). This resulted in a biphasic liquid product with 25.6 wt % of an aqueous phase and 11 wt % of an oil phase. The yield of benzene, toluene, and xylenes was 1.9 wt % (on a biomass basis). Finally, the concept was also proven for a representative polyolefin (polypropylene), both noncatalytic as well as in situ catalytic pyrolysis using H-ZSM-5 as the catalyst at 500 °C. The liquid yield of thermal, noncatalytic plastic pyrolysis was as high as 77 wt % on plastic intake, while in situ catalytic pyrolysis gave a combined 7.8 wt % yield of benzene, toluene, and xylenes on plastic intake.

Microwave-Assisted Pyrolysis of Pine Wood Sawdust Mixed with Activated Carbon for Bio-Oil and Bio-Char Production

Pyrolysis of pine wood sawdust was carried out using microwave-heating technology in the presence of activated carbon (AC). Experimental conditions were of 20 min processing time, 10 wt.% of AC, and a microwave power varying from 100 to 800 W. The results obtained showed that the microwave absorber allowed increasing the bio-oil yield up to 2 folds by reducing the charcoal fraction. The maximum temperature reached was 505 °C at 800 W. The higher heating values (HHV) of the solid residues ranged from 17.6 to 30.3 MJ/kg. The highest HHV was obtained for the sample heated at 800 W with 10 wt.% of AC, which was 33% higher than the non-charged sample heated at the same power. Furthermore, the addition of AC allowed showing the probable catalytic effect of the AC in the charged sample pyrolysis bio-oils.

Investigating the effect of Cu/zeolite on deoxygenation of bio-oil from pyrolysis of pine wood

Pyrolysis is one of the significant technologies that can utilize lignocellulose biomass to produce different bioenergy fuels, such as bio-oil, pyrolytic gases and bio-char. The application of pyrolysis has been extensively studied to produce bio-oil, which is foreseen as the potential transportation fuel in the near future. However, the presence of oxygenated compounds, such as phenols and alcohols in bio-oil makes it highly acidic and unstable for a suitable transportation fuel. These oxygenated compounds can be converted to refinable hydrocarbons by using different catalysts. Therefore, this study aimed to prepare a catalyst that is Cu10%-zeolite and investigated its deoxygenation activity for bio-oil produced from pyrolysis of pine wood sawdust. The catalyst was prepared by a wet-impregnation method. Subsequently, the catalyst was characterized by X-ray diffraction and transmission electron microscopy. Furthermore, the catalyst was applied for in-situ (catalyst: biomass=5) and ex-situ catalytic pyrolysis (catalyst: biomass=3) and the results were compared with those from sole zeolite support. The pyrolysis process was carried out at a heating rate of 100 °C/min to a final temperature of 700 °C and the composition of bio-oil was examined by gas chromatography-mass spectroscopy. The results revealed that Cu-zeolite showed significant deoxygenation activity for bio-oil as compared to zeolite or without any catalyst. Evidently, Cu-zeolite after in-situ pyrolysis produced bio-oil with 20.9% aromatic hydrocarbons and 7.5% aliphatic hydrocarbons, which were approximately 80% and several times higher than with only zeolite, respectively. Meanwhile the concentration of alcohols was reduced from 47.5% to 5%. On the other hand, bio-oil produced from ex-situ catalytic pyrolysis was enriched with 41.6% aromatic hydrocarbons while only 1% alcohols were present in bio-oil. This promising deoxygenation activity can be ascribed to Cu-zeolite’s catalytic activity that converted phenol and alcohols to refinable hydrocarbons via various reactions, such as dehydration, decarboxylation and decarbonylation.

Hydrogen production from biomass by continuous fast pyrolysis and in-line steam reforming

The continuous fast pyrolysis of pine wood sawdust has been studied in a conical spouted bed reactor (CSBR) followed by in-line steam reforming of the pyrolysis vapours in a fluidised bed reactor on a Ni commercial catalyst.

Catalytic Pyrolysis of Pine Wood Sawdust to Produce Bio-oil: Effect of Temperature and Catalyst Additives

In this work, non-catalytic pyrolysis of Turkish pine (Pinus brutia Ten.) wood sawdust was performed in a fixed-bed reactor at various temperatures to obtain the optimum conditions to achieve a maximum bio-oil yield. The highest yield of bio-oil was obtained about 46 wt% at 550°C for non-catalytic pyrolysis. At the optimum conditions, the effects of different catalyst types (KOH, ZnCl2, and ZnO) and amount of catalyst (5, 10, 15, and 20 wt%) on the pyrolysis product yields and bio-oil properties were investigated. The presence of catalysts changed the product distribution considerably. Increasing the amount of catalyst led to a decrease in the yield of liquid product, while the gas and char yields increased compared to non-catalytic pyrolysis. The chemical compositions of bio-oil were determined with GC-MS analyses. It was determined that bio-oils contain a large variety of organic compounds, such as furans, aldehydes, ketones, phenols, acids, benzenes, alcohols, alkanes, and polycyclic aromatic hydrocarbons (PAHs). The catalysis by KOH significantly increased the levels of phenols, while it reduced the formation of acids and aldehydes. ZnCl2 produced bio-oil with high percentages of aldehydes. Moreover, ZnO reduced the proportion of PAH in the bio-oil. These results demonstrated that bio-oils could improve with a catalyst. Therefore, catalyst selection for high bio-oil quality is crucial in industrial applications.

STEPWISE ISOTHERMAL FAST PYROLYSIS (SIFP) OF BIOMASS PART I. SIFP OF PINE SAWDUST

Pyrolysis of pine wood sawdust was carried out using stepwise isothermal fast pyrolysis (SIFP), focusing on the search of reaction conditions to obtain chemicals in good yields from biomass. SIFP consists of successive isothermal fast pyrolysis reactions, where solid products obtained in the previous isothermal fast pyrolysis become the substrate of the subsequent reaction at a higher temperature. This article reports results obtained by SIFP of pine sawdust between 200 and 600°C using 100°C intervals under vacuum (0.2 mm), using nitrogen as carrier gas. Both sets of reactions made it possible to obtain most of the compounds that have been previously described in conventional fast pyrolysis experiments; however this system produces a smaller number of chemical compounds in each isothermal FP, making it easier to obtain determined chemicals with industrial or research value. Maximum yield of liquid products occurred at 300°C, giving around 30% of bio-oil, which contained mainly phenols and furan derivatives. Liquid-Liquid extraction led to a rich mixture of phenol derivatives. Results showed that SIFP is an interesting technique to obtain enriched fractions of products derived from biomass pyrolysis.

Stepwise isothermal fast pyrolysis (SIFP) of biomass. Part 1. SIFP of pine sawdust

Pyrolysis of pine wood sawdust was carried out using stepwise isothermal fast pyrolysis (SIFP), focusing on the search of reaction conditions to obtain chemicals in good yields from biomass. SIFP consists of successive isothermal fast pyrolysis reactions, where solid products obtained in the previous isothermal fast pyrolysis become the substrate of the subsequent reaction at a higher temperature. This article reports results obtained by SIFP of pine sawdust between 200 and 600°C using 100°C intervals under vacuum (0.2 mm), using nitrogen as carrier gas. Both sets of reactions made it possible to obtain most of the compounds that have been previously described in conventional fast pyrolysis experiments; however this system produces a smaller number of chemical compounds in each isothermal FP, making it easier to obtain determined chemicals with industrial or research value. Maximum yield of liquid products occurred at 300°C, giving around 30% of bio-oil, which contained mainly phenols and furan derivatives. Liquid-Liquid extraction led to a rich mixture of phenol derivatives. Results showed that SIFP is an interesting technique to obtain enriched fractions of products derived from biomass pyrolysis.

Production of green aromatics and olefins by catalytic fast pyrolysis of wood sawdust

Catalytic fast pyrolysis of pine wood sawdust and furan (a model biomass compound) with ZSM-5 based catalysts was studied with three different reactors: a bench scale bubbling fluidized bed reactor, a fixed bed reactor and a semi-batch pyroprobe reactor. The highest aromatic yield from sawdust of 14% carbon in the fluidized bed reactor was obtained at low biomass weight hourly space velocities (less than 0.5 h−1) and high temperature (600 °C). Olefins (primarily ethylene and propylene) were also produced with a carbon yield of 5.4% carbon. The biomass weight hourly space velocity and the reactor temperature can be used to control both aromatic yield and selectivity. At low biomass WHSV the more valuable monocyclic aromatics are produced and the formation of less valuable polycyclic aromatics is inhibited. Lowering the reaction temperature also results in more valuable monocyclic aromatics. The olefins produced during the reaction can be recycled to the reactor to produce additional aromatics. Propylene is more reactive than ethylene. Co-feeding propylene to the reactor results in a higher aromatic yield in both continuous reactors and higher conversion of the intermediate furan in the fixed bed reactor. When olefins are recycled aromatic yields from wood of 20% carbon can be obtained. After ten reaction–regeneration cycles there were metal impurities deposited on the catalyst, however, the acid sites on the zeolite are not affected. Of the three reactors tested the batch pyroprobe reactor yielded the most aromatics, however, the aromatic product is largely naphthalene. The continuous reactors produce less naphthalene and the sum of aromatics plus olefin products is higher than the pyroprobe reactor.

Catalytic effects of eight inorganic additives on pyrolysis of pine wood sawdust by microwave heating

In this paper, pyrolysis of pine wood sawdust was carried out by microwave heating at ca. 470 °C under dynamic nitrogen atmosphere. Eight inorganic additives (NaOH, Na 2CO 3, Na 2SiO 3, NaCl, TiO 2, HZSM-5, H 3PO 4, Fe 2(SO 4) 3) were investigated in terms of their catalytic effects on the pyrolysis. All of the eight additives have increased yields of solid products greatly and decreased yields of gaseous products more or less. Yields of liquid products have not subjected to dramatic change. The incondensable gases produced from pyrolysis consist mainly of H 2, CH 4, CO and CO 2. All of the eight additives have made these gases evolve earlier, among which the four sodium additives have the most marked effect. All the additives have made the amount of CH 4 and CO 2 decrease, while all of them except NaCl, TiO 2 and Fe 2(SO 4) 3 have made that of H 2 increase and all of them except Na 2SiO 3 and HZSM-5 have made that of CO decrease. Alkaline sodium compounds NaOH, Na 2CO 3 and Na 2SiO 3 favor H 2 formation most. The most abundant organic component in the liquid products from pyrolysis of untreated sample and samples treated by all the additives except H 3PO 4 and Fe 2(SO 4) 3 is acetol. All the four sodium compounds favor acetol formation reaction and the selection increasing effect follows the order of NaOH > Na 2CO 3 ≈ Na 2SiO 3 > NaCl. TiO 2 goes against the formation of acetol, HZSM-5 has no marked effect on acetol formation. The two dominant organic components identified in the liquid products from pyrolysis of H 3PO 4 and Fe 2(SO 4) 3 treated samples are both fufural and 4-methyl-2-methoxy-phenol. A possible pathway for acetol formation is tentatively proposed.